You can install W3 Total Cache through the Wordpress Admin Panel:
- Login to your WordPress Dashboard.
- Go to Plugins -> Add New.
- Type W3 Total Cache in the search box and enter.
- Click Install Now button and follow by activate plugin link.
Regarding accessing your instance through SSH, could you run the following command:
ssh -i your_aws_generated_key.pem bitnami@instance_ip
Could you try to remove the IP from known_hosts? For that just open /Users/USERNAME/.ssh/known_hosts file and remove the line with the IP address Then, try to SSH again.
Please, click on if you think my answer was helpful